Piston-ring expander



Sept. 16, 1930. J. H. PLATER I PISTON RING EXPANDER Filed July 24, 1929of the piston ring groove.

Patented Sept. 16, 1930 PATENT OFFICE JAMES H. PLATER, 0F BUBBAHK,CALIFORNIA PISTON -RING EXPANDER Application filed July 24, 1929. SerialNo. 380,625.

This invention relates to improvements in piston ring expanders.

An object of the invention is to provide an improved piston ringexpander formed of a strip of resilient material, such as spring steel,and which is polygonal in form, adapted to be placed Within a pistonring to expand the same. i The improved jexpander has for one of itsnovel features of construction crimps which define the sides of thepolygonal strip. These crimps are novel in that they are non-paralleland are arranged in converging pairs, converging toward one side edge ofthe strip. By having the crimps so formed, the crimps form inclinededges which are slightly inclined toward the vertical central axisthrough the piston, to which the expander may be applied, so that whenthe expander presses outwardly against the inner side of the piston ringthese inclined edges have the tendency of urging the ring toward oneside In this way the expander not only serves to expand the piston rinbut tends to keep the piston ring urged tightly against one side of thering groove, assisting in preventing leakage around the ring.

The improved piston ring expander is also advantageous in that it may beas easily and quickly constructed as expanders heretofore produced andwill have the advantages present which are above mentioned.

Another object of the invention is to provide a piston ring expanderadapted to be used in conjunction with an oil ring, which oil ring hasapertures therethrough, and the expan or is so constructed as tomake'provision for the flow of oil through the ring and by the expanderthrough bleeding ports which may be formed in the piston.

With the foregoing and other objects in view, which will be mademanifest in the following detailed description, and specifically pointedout in the appended claims, reference is had to the accompanyingdrawings for an illustrative embodiment of the invention, wherein:

Fig. 1 is a horizontal section through a piston and cylinderillustrating the improved piston ring expander in applied positiontherein.

Fig. 2 is a view in side elevation of one wherein similar referencecharacters des1g-- nate similar arts throughout, the reference characterC esignates a cylinder in which a piston P is reciprocable. The pistonis shown as having one or more rin grooves G in which piston rings R arec lisposed, which may be of any conventional construction. The. improvedpiston ring expander colnprises a strip 0 resilient material, such asspring steel, which is polygonal in form and generally conforms to theshape of a circle. This strip of spring steel is indicated at 10, havina plurality of sides 11 which are defined rom each other by crimps 12and 13. The crimps 12 and 13 are arranged in pairs and are non-parallel.That is, the .crimps 12 and 13 of each pair converge toward each othertoward one side edge of the strip 10.

By the improved construction when the expander is disposed within thering groove G the outer surfaces of the crimps vwill present edges whichare inclined slightly toward the longitudinal central axis through thepiston these inclined edges, the expander will serve not onl to expandthe ring R against the walls 0 the cylinder C, but it will also have thetendency to urge the ring R a ainst the top of its ring groove. Whethert e ring R is urged toward the top or bottom of its ring groove dependson whether the expander is right side up, as shown in Fig. 2, or in aninverted position.

The piston ring expander shown in Fig. 3 is of the same generalconstruction as that shown in Figs. 1 and 2 and comprises a section orstrip of spring steel 15 having convergingpairs of criln s 16 and 17defining the sides of the expan er. This expander is designed to be usedin conjunction with an oil ring through which passages may be formed,and to allow the flow of oil through P. Consequently by virtue of :2 v1,77e,ooa

' the' oil ring and through bleeding ports formed in the piston.Portions of one edge of the expander are removed, as indicated at 18.These removed portions are preferably arranged across ends of the crimps16 and-17 and extend slightly therebeyond. They form passages at thisedge of the expander throughwhich oil, passin through the 011 ring, canpass to reach t e bleeding ports through the piston,

From the above described construction it will be appreciated that animproved piston ring expander is provided which is advantageous in thatthe expander serves not only to expand the ring R but urges it againstone side of the ring groove and tends to keep it N there. This has theeffect of decreasing leakage around the rings. The improved expanderalso provides a construction which maybe suitably and advantageouslyemployed in conjunction with an oil ring.

- The'expander disclosed herein has an important advantage in that theformation of 4. A piston ring expander comprising a strip of resilientmaterial adapted to be pothe crimps facilitates the insertion of thering in the ring groove. While the improved expander can be used withany conventional form of ring, it has been designed to be used inconjunction with the ring disclosed in my copending application, SerialNo. 380,624,

filed July 24, 1929, wherein the ring has an interior annular bead orridge at about its center in which the inclined edges at the crimps willbear and become effective in urging the ring against a side of the ringgroove. Various changes may be made in the details of constructionwithout departing from the spirit or scope of the invention as definedby theappended claims.

I claim: 1. A piston ring expander comprising a strip of resilientmaterial, polygonal m form, and having sides defined from each other bypairs of non-parallel crimps.

2. A piston ring expander comprising a strip of resilient material,polygonal in form,

and having its sides defined from each other by pairs of convergingcrimps.-

. 3. A piston ring expander comprising a strip of resilient material,polygonal in edge elevation, and havin its sides defined from each otherby pairs 0 converging crimps, all

0f the crimps of their respective pairs converging toward one edge ofthe strip.

sitioned in a piston ring groove within a piston ring,said expanderpresentin edges toward the piston ring which are s 'ghtly inclinedtoward the longitudinal central axis through the piston. 1

In testimony whereof I have signed my 7 name to this specification.

JAMES H. PLATER.

